Massachusetts three-decker: energy retrofit during re-siding
We have a three decker In Climate zone 5 with 2×4 walls that we are going to reside with fiber cement. We have 2 different wall cavity insulation types. The first floor has close cell spray foam of about R-20. The second and third floor have “ancient” loose filled blown in cellulose. We plan to have our 2nd and 3rd floor “refilled” with dense pack blown in cellulose. I am concerned about what type of foam panel insulation we should put since we have two types of cavity insulation and need to avoid moisture problems from the first floor closed cell spray foam. Do we have to treat our 1st floor differently than our 2nd/3rd floors. Can we use regular house wrap or does it have to something like “hydrogap”?